Electrically driven floor tending and cleaning machines



Naif. 26, 1968 H. BRAB 3,412,415

ELECTRICALLY DRIVEN FLOOR TENDING AND CLEANING MACHINES Filed June 5, 1965 6 Sheets-Sheet 1 Inventor.- J u berZ- 2574b Wm Mg QM ATTO FNE Y8 Nov. 26, 1968 H. BRAB 3, 2, 5

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ELECTRICALLY DRIVEN FLOOR TENDING AND CLEANING MACHINES Filed June 5, 1965 v 6 Sheets-Sheet 3 Fig.4

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ELECTRICALLY DRIVEN FLOOR TENDING AND CLEANING MACHINES Filed June 3, 1965 s Sheets-Sheet 5 In ventor:

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ELECTRICALLY DRIVEN FLOOR TENDING AND CLEANING MACHINES Filed June 3, 1965 6 Sheets-Sheet 6 Fig. I!

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I in van for: ffuberf Zfrab 4a 30%, M @m/ ATTORNEYS United States Patent 3 412,415 ELECTRICALLY DiIIVEN FLOOR TENDING AND CLEANING MACHINES Hubert Brab, Richterich, Germany, assignor to Messrs. Vertex-Vertriebsgesellschaft mit beschrankter Haftung, Aachen, Germany, a corporation of Germany Filed June 3, 1965, Ser. No. 460,911 Claims priority, application Germany, June 10, 1964, V 26,129 16 Claims. (CI. 15-50) ABSTRACT OF THE DISCLOSURE A fioor polishing and cleaning machine is provided whereby an electric motor drives a tool through a starting or overrunning clutch and reduction gearing. The clutch is operative to prevent driving of the tool until the motor has rached its normal drive speed and torque. The machine incl-udes a housing portion and a handle portion which is pivotally connected to the housing portion and removable therefrom. A dual safety device is provided in the handle portion for preventing accidental starting of the motor. The starting clutch and reduction gearing may also comprise a hydraulic gearing assembly. Means are provided for connecting auxiliary devices, such as a wax spray device to facilitate floor polishing.

The present invention concerns an electrically driven floor tending and cleaning machine having a shaft flexibly engageable on the machine housing and supporting the switching elements and a tool comprising one or more revolving working wheels supported on the floor.

Known machines of this kind have several disadvantages. In most cases considerable mains fuses are required in order to absorb the high load impulse current of the machine upon starting. In many cases such a machine is not readily operable due to the lack of such fuse arrangement.

It has therefore been attempted to find means which permits the high starting currents to be reduced. Thus, for example, it has been proposed to construct the tool so as to be raisable and lowerable. This embodiment however is very cumbersome and requires a considerable overall height.

Particularly in connection with floor treating machines it is important for the machine to be made as flat as possible in order to enable them to be used beneath radiators, wardrobes or the like. Such an operation fails in most cases due to the excess height of the motor mounted above the tool, and in other cases the motor is mounted in a cumbersome position at the front end of the machine housing.

An alternaive proposal to obtain smooth starting consists in mounting the tool resiliently in springs engaging the circumference of the tool. This embodiment which is also very complex in fact provides smooth starting, but does not prevent the high mains loading on starting.

The present invention is based on the clear knowledge of these conditions with the object of developing an embodiment of such a machine which eliminates the said disadvantages and moreover has a lower overall height, and is simple in manufacture and operation and operationally reliable.

The solution to such problems previously mentioned consists in that in known manner a prime mover in the form of a single phase squirrel cage induction motor drives the tool via a reduction device which rotates the tool'only on exceeding a certain starting speed of the prime mover at full torq-ue.

3,412,415 Patented Nov. 26, 1 968 A preferred embodiment of such a machine consists in that the prime mover comprises an annular stator arranged concentrically in the machine housing and a rotor which is also annular and arranged concentrically therein without a driven shaft and that the reduction device is enclosed by the rotor. This novel motor structure permits an extremely low overall height of the machine. Moreover all moving machine components are enclosed by the protecting ring of the motor.

A favourable further embodiment of the present invention is that a mechanical reduction gearing is provided which is connected at the driving end to the driven part of a starting clutch, which is so constructed that it does not transmit the full torque until exceeding the graph saddle in the Torque-Speed diagram of the prime mover.

It is thus advantageous for the starting clutch to be constructed in the form of a centrifugal clutch enclosed by the prime mover, the jaws of the clutch being pivotally mounted on an anchor plate rigidly connected to the rotor and the driven part of which or clutch housing supports a driving shaft for the reduction gearing.

A further measure for saving space consists in that the reduction gearing is constructed in the form of a single stage epicyclic gearing having a crosspiece between planetary gears which supports the driving shaft for the tool. The epicyclic gearing also has a further advantage relative to spur gear reduction that constantly as many teeth are in engagement as there are epicyclic gears. In this case a small tooth modulus is possible whereby a good power transmission and reduction is ensured.

A further development of the invention consists in that the space enclosed by the stator and the machine housing is oil sealed to receive a charge of oil. This permits good lubrication and cooling to be obtained.

In accordance with an alternative embodiment of the machine according to the invention, provision is made for the reduction gear together with the starting clutch consisting of a hydraulic gearing in the manner of a Foettinger gearing, which is driven directly by the prime mover. A hydraulic gearing combines the capacities of a starting clutch and a reduction gearing. By suitable, simple means it is even possible to control the speed of the driven shaft which in certain cases is advantageous. Furthermore the hydraulic gearing requires a very slight overall height and practically no maintenance.

In known machines a disadvantage is encountered in that the space between the tool carrier and the tool the clearance is either too slight or too wide. In the first instance the tool is removed from the tool carrier only with difficulty. In the latter case irksome noises and damage occur in the machine.

Despite these deficiencies no attempts have heretofore been made to remedy this. Instead of the former rigid mounting of the tool on the tool carrier it is therefore proposed for a revolving flange-like tool carrier to be mounted on the driven shaft and which on sectors of its underside has clip-like springs for retention thereon of known supporting straps carried by and secured to the tool housing.

A further feature of the known machine consists in that it may happen that the machine is started inadvertently. This, for example, may happen if a feed cable is twisted round the hand grips and the switch lever thus switching the machine on.-Accidents and considerable damage may occur thereby. To avoid these disadvan-' tage s it is therefore proposed that the handle has a safety device to ensure against the inadvertent switching on of the machine. This may for example be rendered possible by the fact that the safety device consists of at least one switch element mounted on the handle of the shaft for actuating a toggle lever rod system which acts on a microswitch which isolates the mains from the prime mover or of a further switching element causing the unlocking the toggle lever mechanism or microswitch.

A further deficiency of the previous machines is regarded in the fact that the shaft adapted to be adjustable in its pivotal position has excessive clearance relative to the machine housing. This is based on the necessarily large space required by the customary pawl arrangement.

In order to overcome this disadvantage it is therefore proposed in accordance with the inventionthat the lower end of the shaft pivotally mounted on a pivotal axis of the machine housing in known manner is adapted to be located in known manner by means of a manually actuated pawl engageable on a toothed portion for pivoting the pawl about a stop axis concentric with the pivotal axis, the pawl thus being rigidly mounted on the machine housing in any of various angular positions relative the floor. To avoid any tooth clearance between stop axis and shaft a friction stop or a friction brake is provided.

A further advantageous embodiment of the invention consists in that the pivotal axis is mounted in the lower shaft housing with its ends adapted to be inserted in slotted pedestal bearings of the machine frame, and at the end face of the stop axis a pin also projecting in the slot of the associated pedestal bearing is mounted as security against twisting. This permits the shaft to be detached from the machine housing. This is particular advantageous when shipping the machine. It is also possible for the complete shaft to be changed for another should repair be necessary or a different length of shaft be required.

In known machines of the kind in question herein it is still customary today to apply the liquid polish by hand on the floor. The application of polish is thus naturally extremely uneven and leads to excessive consumption of polish. This on the one hand is costly and on the other hand is harmful to the floor.

In accordance with the invention it is proposed for a spraying device for liquid pOliSh to be detachably mounted on the machine housing.

The present invention will now be described by way of example with the aid of the accompanying drawings in which:

FIG. 1 is a side view of the floor polishing machine,

FIG. 2 is a plan view thereto,

FIG. 3 is an enlarged longitudinal section through the machine housing,

FIG. 4 is a plan view of the tool carrier,

FIG. 5 is a side view of the tool carrier,

FIG. 6 is a partial longitudinal sectional vie-w through a tool carrier,

FIG. 7 is a longitudinal section through a safety device guarding against inadvertent switching on of the machine,

FIG. 8 is a longitudinal section through an alternative safety device,

FIG. 9 is a longitudinal section through the lower shaft housing of the machine,

FIG. 10 is a side view of the lower shaft housing,

FIG. 11 is a longitudinal section through a polish spraying device, and

FIG. 12 is a partial longitudinal section through a modi fied embodiment of the polish spraying device.

The novel floor polishing and cleaning machine as shown in FIGS. 1 and 2 has a machine housing 2 carrying the tool 1 (illustrated in FIGURE 5) and on which centrally the prime mover 3 is arranged. Pivotally mounted on the [machine housing 2 is a shaft 4 preferably comprised of two tubes having at its upper end a handlebarlike handle 5.

In FIGURE 3 the machine housing 2 of the machine is shown in detail in section. The drawing thus shows the machine housing shortened in a radial direction.

In accordance with the drawing the machine housing 2 comprises a circular shell which covers the tool 1. In the centre of the machine housing 2 a housing bottom 6 4 is formed which has a central boss 7 to receive the driving shaft 8 of the tool 1.

On the housing bottom 6 the prime mover 3 of the machine is mounted. The latter is constructed in the form of a shaftless annular single phase squirrel cage induction motor and comprises an annular stator 9 in which a rotor 11 also annular is rotatably guided in the machine housing and the winding 10 arranged between stator and rotor.

The upper edge of the rotor 11 is firmly connected to an armature plate 12 closing the rotor in a cover-like manner.

In the cavity enclosed by the armature plate 12, the rotor 11 and the housing bottom a reduction device generally designated by the numeral 13 is accommodated.

In the example shown in FIGURE 3 the reduction device comprises a starting clutch 14 and the actual reduction gear 15, which in the present case is in the form of an epicycylic gear.

Individually the power transmitting members are arranged as follows:

Pivotal levers 16 are journalled to the armature plate 12 distributed over a pitch circle at the ends of which pivotal levers clutch shoes 17 are mounted which by means of a suitable friction lining 17' are adapted to contact the inner wall surface of the clutch housing 18. This clutch housing 18 forms the driven part of the clutch. The two oppositely disposed clutch shoes 17 are braced outwardly by means of a suitable compression spring 18'. The clutch is so arranged that, when the prime mover3 has started, i.e., at a motor speed below the known saddle in the Md/n or torque-speed characteristic line of a single phase squirrel-cage induction motor, only transmits the full troque to the gearing connected at the end. On reaching this speed the centrifugal force acting on the clutch shoes 17 causes them to be pressed outwardly against the clutch housing 18 and to produce a positive coupling of the prime mover 3 with the reduction gearing.

As evident from the drawing, the clutch housing mounted rotatably relative to the rotor has a driven shaft 19 which simultaneously acts as the driving shaft of the sun wheel 20 of the epicyclic gearing; The sun wheel preferably meshes with three epicyclic gears which are enclosed by an internally toothed spur ring 21 and are munted on a revolving rib 22 with their journals 23. The rib 22 has a downwardly facing shaft end 8 which simultaaneously acts as driving shaft for the tool 1.

The prime mover 3 is completely closed at its top end by a housing cover 24. The space 25 enclosed by the prime mover and the machine housing is sealed off and thereby oil-tight and charged with oil. This on the one hand serves the obect of machine lubrication and on the other hand the necessary cooling of the machine.

Mounted firmly splined to the lower end of the driving shaft 8 of the tool is flange-like tool carrier 26. On its underside, as evident especially from FIGURES 4 and 5, it has three clip-like springs, e.g., plate springs 27, each of which is firmly connected to a portion of the tool carrier.

As shown in FIG. 4 the workpiece 1 has an annular supporting plate 28 which has sector-like supporting straps 29 projecting inwardly. By means of these supporting straps 29 the tool 1 is fitted against the underside of the tool carrier and rotated somewhat relative thereto, so that the supporting straps assume a position between the underside of the tool carrier and the clip-like spring 27 and thereby avoids tolerance difiiculties frequently occurring in other machines.

FIGURE 6 shows an alternative embodiment of a reduction gearing. In accordance with the invention the starting clutch and the reduction gearing may also be replaced by a hydraulic gearing 30 in the form of a conventional torque converter which on the one hand takes over the task of the starting clutch and on the other. hand a possibly even variable speed reduction. This hydraulic gearing is extremely space saving and expedient. In the case of a prime mover having an annular rotor it may be accommodated within the rotor or, as shown in FIGURE 6, even below a standard single phase squirrelcage induction motor 3' of an extremely flat design, on the housing bottom 6.

FIGURE 7 shows the upper end of the shaft 4. The two tubular shafts 4 terminate in a rigid housing casing 31, from which, in the manner of handlebars, flanged pipe sockets 5 project and serve as handle.

On the inner ends of these flanged pipe sockets a switching element 32 formed as a double-armed lever is mounted, one lever arm of which projecting out through a slot in the handle 5. The other lever arms 33 projecting into the housing 31 engage a toggle lever rod mechanism 34. The latter individually comprises a crank lever 35 journalled to the lever arms 33, on the apex 36' of which a further lever arm 37 is rigidly secured. Furthermore a downwardly suspended lever 38 is journalled to the apex 36, the lower end of the lever being hingedly connected to the end of a push-rod 40 actuated by means of a pushbotton 39 mounted on the housing 31.

A micro-switch 41 is suspended on the lever arm 37 and supported by means of a spring 42. Moreover in the extension of the lever arm 37 an actuating tongue 43 is mounted which is adapted to act on the switch pin 44 of the micro-switch 41. On the side of the micro-switch facing the lever 38 a cranked guide tongue 45 is mounted which is supported against a guide bolt 46 which is rigidly connected on the lever 38. The said parts together form a switching and safety device.

The micro-switch 41 isolates the prime mover from the mains. To provide the prime mover with electric currentit is first necessary to depress the push-button 39. The latter causes a slight deflection of the lever 38 away from the micro-switch. In this case the guide bolt 46 slides over the curve of the guide tongue.

If one or both of the two switching elements 32 is pulled in the direction of the handle 5, then the lever arm 33 is now able to move the lever 38 downwardly via the cranked lever 35. Thus, the micro-switch is tilted to such an extent that its switch pin is depressed against the force of the tongue 43. Hence any inadvertent switching of the machine is eliminated.

FIGURE 8 shows an alternative emodiment of a mechanical safety device. In its essential structure it has the same elements as the device according to FIGURE 7. The samt elements are therefore provided with the same reference numerals.

As shown in the drawing, the micro-switch has a continuous switch pin 44', which in contrast to the switch pin 44 is not spring-loaded. On the lower end of this switch pin 44' a cranked lever 47 engages, which replaces the lever 38, the guide bolt 46 and the guide tongue 45 of the first mentioned device are adapted to be displaceable by the inner end of the push-button 39.

The switching on position herewith is reversed as in the first described device:

The switching elements on the handle are first actuated. This causes the apex 36 to be somewhat lowered and to swing the micro-switch 41 horizontally. By depressing the push-button 39 the cranked lever 47 is swung about which engages the switch pin 44 ad hence causes the contacts in the micro-switch to make contact with one another.

This embodiment is extremely simple and space saving. Other safety devices, e.g. electrical ones are conceivably feasable and known per se.

In accordance with FIGURE 9 on the lower end of the shaft 4 a shaft housing 48 is disposed in which the electrical control elements 49, e.g., condensers, etc., are accommodated. On its lower end a pivotal axis 50 is rotatably mounted relative to the shaft housing 48. Mounted on this shaft axle rigidly connected thereto is a toothed stop axle 51 in which a pawl 52 guided in the shaft housing 48 engages. This pawl is connected via a Bowden cable 53 to a draw-lever, not shown.

In order to compensate tolerances in tooth clearance a friction stop is provided. The latter comprises a plate spring 58 axially supported against a shoulder 55 of the pivotal axis 50, which spring urges a friction disc 57 against the end face of a bearing 56 of the shaft housing. The whole adjusting system is braced positively in this manner.

As shown in detail in FIGURE 9 and especially FIG- URE 10, the pivotal axis 50 projects on both sides beyond the shaft housing 48. These projecting ends 59 rest in bearings 60 of pedestal bearings 61 which are rigidly connected to the machine frame 2 (FIG. 1).

As'shown in FIGURE 10, the pedestal bearings 61 have slots 62 for inserting the axle ends 59 which .are firmly screwed to the pedestal bearings. As a safeguard against twisting a pin 63 also engaging in the slot 62 is furthermore provided, which projects from the end face of the axle and possibly from a bearing bush on the other axle end. This arrangement permits the shaft to be connected simply to the machine frame.

In accordance with FIG. 9 the lower shaft housing has a socket 64 supported thereon by means of which a switch (not shown) is arranged on the upper shaft housing is adapted to be connected to the mains. This socket is suitable for connecting various auxiliary devices, such as spraying devices or a liquid reservoir 78.

To enable the floor to have liquid polish evenly applied thereto a spraying device 66 is suitably mounted on the machine housing 2 in any conventional manner, the details of the mounting of the spraying device on the housing 2 not being a part of this invention.

The latter conveniently comprises a container 67 for the liquid polish and at its base has a pump 68 connected with the interior of the container. This pump is connected with a spraying nozzle 69.

As shown in FIGURE 11 the pump consists of a piston 70 the connecting rod 71 of which is actuated by a conventional solenoid 72. During its stroke movement the piston exposes an outlet opening 74 leading from the reservoir 67 into the injection passage 73 and forces the emitted polish supply to the spraying nozzle.

FIGURE 12 shows an alternative pump construction. Herein a piston 70 possibly actuated manually is provided. From the cylindrical base of this piston an air pipe 75 leads to the spraying nozzle which by means of a supply pipe 76 is connected to the interior of the container. The piston pressure causes in known manner an injector action.

Further embodiments of a spraying device are conceivable. Thus, it is possible to subject the container to air pressure and for the liquid polish to be omitted through a suitable, e.g., valve-controlled opening.

I claim:

1. An electrically operable floor polishing and cleaning machine comprising a machine housing, a handle member having a handle shaft in pivotal engagement with a rearward portion of said housing, said handle member carrying switching means, and at least one rotatable working tool operatively carried by said housing, including a driving electric motor, reduction drive means operatively connected to said tool in driving relation therewith, starting clutch means for automatically coupling said tool and said motor after said motor has reached its normal driving torque, a single control switch and safety switching means for said switch including means for preventing inadvertent switching on of the machine, and auxiliary polishing means.

2. The machine of claim 1 wherein said auxiliary polishing means comprising a spraying device, detachably mounted on said housing, said spraying device including a container for receiving liquid polish, and a spraying nozzle and a pump connected to the lower end of said device.

3. The machine of claim 2 wherein said pump comprises a piston and a piston rod, having means for displacing said piston, including a solenoid connected to the piston rod.

4. An electrically operable floor polishing and cleaning machine comprising a machine housing, a handle member having a handle shaft in pivotal engagement with a rearward portion of said housing, said handle member carrying switching means, and at least one rotatable working tool operatively carried by said housing, including a driving electric motor, reduction gear means operatively connected to said tool in driving relation therewith, starting clutch means for automatically coupling said tool and said motor after said motor has reached its normal driving torque, safety switching means for preventing inadvertent switching-on of the machine, and auxiliary polishing means, said motor comprising an annular stator centrally arranged in said machine housing and an annular rotor arranged concentrically therein without a driven shaft, and the reduction gear means being disposed within said rotor.

5. The machine of claim 1, wherein said reduction drive means is a mechanical gear unit, and is connected at its driven end to a driven part of said clutch means; said clutch means being so constructed that it does not transmit the full motor torque until the motor speed has increased beyond the level of high starting torque.

6. The machine of claim in which the starting clutch means comprises a centrifugal clutch disposed within the rotor of the motor; said clutch including shoes, an aramature plate, and a clutch housing; said shoes being pivotally mounted on said armature plate; said plate being connected to the rotor; and wherein said clutch housing comprises a driven member which supports a driving shaft for the reduction gear means.

7. The machine of claim 1 wherein the safety switching means comprises at least one switch element mounted on said handle member, a toggle lever rod mechanism, a secondary switch element; said one switch element being adapted for actuating said toggle lever rod mechanism for actuating said control switch for connecting a source of power supply to the motor, said secondary switch element normally being operable to cause a selected one of the toggle lever rod mechanism and the control switch to be inoperable, and said secondary switch element being manually movable to a position facilitating the operation of said control switch by said one switch element.

8. The machine of claim 1, wherein, said housing is provided with a pivot axis on which said handle member is pivotally mounted, a toothed stop axle is mounted concentric with said pivot axis and said handle has a manually actuateable pawl releasably engaged with said axle, said axle being fixedly mounted on said machine housing whereby said pivotal handle shaft is pivotal about a pivotal axis and can be disposed at variable angles relative to a bottom surface of said tool in order to avoid tooth clearance, and wherein a friction brake is operatively disposed between said stop axle and said handle shaft.

9. The machine of claim 8, wherein said friction brake comprises a plate spring supported against the pivotal axis by a shoulder thereof, and a friction disc; said disc being pressed against a lower portion of said shaft housing by said spring.

10. The machine of claim 8, wherein slit pedestal bearings are provided on the machine housing, the pivotal axis being disposed in a lower portion of the shaft housing wherein ends of the pivotal axis are adapted to be inserted into the slit pedestal bearings, and wherein a pin is provided, projecting from an end face of said stop axle into said slit, to prevent twisting.

11. The machine of claim 1 wherein said auxiliary means comprises a spraying device including a container for receiving liquid polish, a spray nozzle for receiving polish from said container, an air supply pipe positioned within said spray nozzle for providing an injection action, and a pump for supplying air under pressure to said air pipe.

12. An electrically operable floor polishing and cleaning machine comprising a machine housing and at least one rotatable working tool operatively carried by said housing, including a driving electric motor, reduction drive means operatively connected to said tool in driving relation therewith, starting clutch means for automatically coupling said tool and said motor after said motor has reached its normal driving torque, the motor comprising an annular stator centrally arranged in said machine housing and an annular rotor arranged concentrically therein without a driven shaft, the reduction drive means being disposed within said rotor.

13. The machine of claim 12, wherein the reduction drive means comprises a single stage epicyclic gearing, including sun, planetary and outer gears, the planetary gears having a connecting web Which supports the driving shaft for the tool.

14. The machine of claim 12 wherein the space enclosed by the rotor and the machine housing is oil-tight and adapted to receive an oil charge.

15. The machine of claim 12, wherein the reduction drive means together with the starting clutch means comprises a hydraulic drive directly driveable by the motor.

16. The machine of claim 12 in which the starting clutch means comprises a centrifugal clutch disposed within the rotor of the motor; said clutch including shoes, an armature plate, and a clutch housing; said shoes being pivotally mounted on said armature plate; said plate being connected to the rotor; and wherein said clutch housing comprises a driven member which supports a driving shaft for the reduction gear means.

References Cited UNITED STATES PATENTS 2,039,860 5/1936 Watts 15-410 X 2,785,424 3/1957 McMaster et a1. 15-49 2,958,881 11/1960 Kazimierczak 15-50 2,985,800 5/1961 Cook 200-157 X 3,058,136 10/1962 iRachlin 15-50 3,264,674 8/1966 Doyle et al. 15-328 1,869,179 7/1932 Yutzler et a1. 15-49 2,879,528 3/1959 Finnell 15-50 3,099,028 7/1963 Ardito 15-50 3,286,290 11/1966 Marth 15-49 EDWARD L. ROBERTS, Primary Examiner. 

